6 ms·

Yes, via building/construction codes.

adrr 3y ago
And we are stuck on AC which is a terrible and wasteful way to move electricity. How much energy is wasted converting AC to DC?
- ghouse 3y ago
  Rectifiers (which convert AC to DC) are quite efficient. Apparently up to 98% [0] And then there is the voltage conversion, which traditionally happened on the AC side (inexpensive and simple AC transformers are generally why the transmission and distribution systems are AC). Modern power supplies allow for buck/boost on the DC side. USB-C power supplies are above 90% efficient. [1] [0] https://eepower.com/new-industry-products/huawei-claims-most-efficient-rectifier-at-98-conversion-efficiency/ https://eepower.com/new-industry-products/huawei-claims-most... [1] https://www.ti.com/lit/ug/tidudw2c/tidudw2c.pdf?ts=1683500425525& https://www.ti.com/lit/ug/tidudw2c/tidudw2c.pdf?ts=168350042...
- phkahler 3y ago
  >> And we are stuck on AC which is a terrible and wasteful way to move electricity. That's a really strange thing to see here on HN. Where did you get this idea? BTW Europe having 3-phase AC to the home is brilliant. Wish we had that in the U.S.
  - adrr 3y ago
    Fact that the US main power distribution network(eg: pacific DC intertie)runs on DC that we concert back to AC for regional distribution and then back to DC to power our houses like lights, tv, electronics etc. AC is inefficient long distances and still needs to be converted to DC to power our stuff.
    - phkahler 3y ago
      Most long distance distribution in the U.S. is AC. AC/DC conversion at high voltage and power is a pain, as is DC/DC voltage change.
  - rektide 3y ago
    Three phase to the home?! Whaattt?! If you want to rectify yourself some DC power, 3-phase is awesome. Are there three phase sockets available? I'd think you could build things like high power audio amplifiers or power supplies at radically better price points, if this were actually usable from the wall in places.
    - crote 3y ago
      There is IEC 60309, but those are too bulky to be practical for home use. Three-phase power is basically only used for permanently installed equipment, like an electric stove, heat pump, car charger, or solar panels.
    - jfengel 3y ago
      How is 3-phase better for rectifying? Is it because it's easier with them 120 degrees out of phase rather than 180?
      - phkahler 3y ago
        You always have power available at any instant. The capacitor is only for smoothing the ripple, not holding energy while none is being delivered. 3-phase motors just work too.
      - rektide 3y ago
        https://en.wikipedia.org/wiki/Rectifier#/media/File:3_phase_rectification_2.svg https://en.wikipedia.org/wiki/Rectifier#/media/File:3_phase_... shows the visual of what full-wave 3-phase rectification is. Note how very low the ripple is between the high and the low of these peaks. 3 phase is 120 degrees out of phase. Wall power only has a single phase, 360 degrees. Via +/- rectification the situation gets more complex. The key thing, as the other commenter points out, is that there is always always power available. Where-as with wall-power you literally drop to zero voltage as you go + to - & back.
  - midoridensha 3y ago
    >That's a really strange thing to see here on HN. Where did you get this idea? Why is this strange? I see this kind of ignorant nonsense here all the time. This site is absolutely full of software people who, because of Dunning-Kruger, think they're experts at everything technical. Electrical engineering isn't that far from the software world (computers are electrical, and their design is within the EE world), so software people frequently think they're experts at anything EE when in fact they don't even understand Kirchoff's Laws, much less the realities of modern-day AC and DC power transmission. There's been multiple discussions here in recent months with these people advocating absolutely idiotic stuff like a whole-house 5V DC supply, showing they don't even understand Ohm's Law. On a side note, it's very frequent that I see posts here from people who apparently have never heard of an ad-blocker, yet are complaining about ads.
    - adrr 3y ago
      I guess you never been in a data center in the last 10 years. All modern DCs run on DC power because stepping down voltage is easy and 95%+ efficient. Why do we backhaul electricity across the country by DC and convert into AC to our house and then back into DC for our stuff? Add renewable energy generation like solar cells and battery storage and AC makes no sense. Theres a reason why china is spinning up DC power grids while posts like mine get bashed on.
      - joenathanone 3y ago
        Data Centers that use DC still have AC to the racks, then a UPS or similar device converts to DC and distributes to the equipment on the rack. DC is inefficient for long distance, unless you are talking HVDC which is another story and it is disingenuous to act like they are comparable.
- ISL 3y ago
  AC came to predominate precisely because it is easier to work with at an infrastructure level. Stepping voltages with transformers is simple and easy. If you're AC all the way, there's never a need to rectify your generator, either.

adrr 3y ago

And we are stuck on AC which is a terrible and wasteful way to move electricity. How much energy is wasted converting AC to DC?

ghouse 3y ago
Rectifiers (which convert AC to DC) are quite efficient. Apparently up to 98% [0] And then there is the voltage conversion, which traditionally happened on the AC side (inexpensive and simple AC transformers are generally why the transmission and distribution systems are AC). Modern power supplies allow for buck/boost on the DC side. USB-C power supplies are above 90% efficient. [1] [0] https://eepower.com/new-industry-products/huawei-claims-most-efficient-rectifier-at-98-conversion-efficiency/ https://eepower.com/new-industry-products/huawei-claims-most... [1] https://www.ti.com/lit/ug/tidudw2c/tidudw2c.pdf?ts=1683500425525& https://www.ti.com/lit/ug/tidudw2c/tidudw2c.pdf?ts=168350042...
phkahler 3y ago
>> And we are stuck on AC which is a terrible and wasteful way to move electricity. That's a really strange thing to see here on HN. Where did you get this idea? BTW Europe having 3-phase AC to the home is brilliant. Wish we had that in the U.S.
- adrr 3y ago
  Fact that the US main power distribution network(eg: pacific DC intertie)runs on DC that we concert back to AC for regional distribution and then back to DC to power our houses like lights, tv, electronics etc. AC is inefficient long distances and still needs to be converted to DC to power our stuff.
  - phkahler 3y ago
    Most long distance distribution in the U.S. is AC. AC/DC conversion at high voltage and power is a pain, as is DC/DC voltage change.
- rektide 3y ago
  Three phase to the home?! Whaattt?! If you want to rectify yourself some DC power, 3-phase is awesome. Are there three phase sockets available? I'd think you could build things like high power audio amplifiers or power supplies at radically better price points, if this were actually usable from the wall in places.
  - crote 3y ago
    There is IEC 60309, but those are too bulky to be practical for home use. Three-phase power is basically only used for permanently installed equipment, like an electric stove, heat pump, car charger, or solar panels.
  - jfengel 3y ago
    How is 3-phase better for rectifying? Is it because it's easier with them 120 degrees out of phase rather than 180?
    - phkahler 3y ago
      You always have power available at any instant. The capacitor is only for smoothing the ripple, not holding energy while none is being delivered. 3-phase motors just work too.
    - rektide 3y ago
      https://en.wikipedia.org/wiki/Rectifier#/media/File:3_phase_rectification_2.svg https://en.wikipedia.org/wiki/Rectifier#/media/File:3_phase_... shows the visual of what full-wave 3-phase rectification is. Note how very low the ripple is between the high and the low of these peaks. 3 phase is 120 degrees out of phase. Wall power only has a single phase, 360 degrees. Via +/- rectification the situation gets more complex. The key thing, as the other commenter points out, is that there is always always power available. Where-as with wall-power you literally drop to zero voltage as you go + to - & back.
- midoridensha 3y ago
  >That's a really strange thing to see here on HN. Where did you get this idea? Why is this strange? I see this kind of ignorant nonsense here all the time. This site is absolutely full of software people who, because of Dunning-Kruger, think they're experts at everything technical. Electrical engineering isn't that far from the software world (computers are electrical, and their design is within the EE world), so software people frequently think they're experts at anything EE when in fact they don't even understand Kirchoff's Laws, much less the realities of modern-day AC and DC power transmission. There's been multiple discussions here in recent months with these people advocating absolutely idiotic stuff like a whole-house 5V DC supply, showing they don't even understand Ohm's Law. On a side note, it's very frequent that I see posts here from people who apparently have never heard of an ad-blocker, yet are complaining about ads.
  - adrr 3y ago
    I guess you never been in a data center in the last 10 years. All modern DCs run on DC power because stepping down voltage is easy and 95%+ efficient. Why do we backhaul electricity across the country by DC and convert into AC to our house and then back into DC for our stuff? Add renewable energy generation like solar cells and battery storage and AC makes no sense. Theres a reason why china is spinning up DC power grids while posts like mine get bashed on.
    - joenathanone 3y ago
      Data Centers that use DC still have AC to the racks, then a UPS or similar device converts to DC and distributes to the equipment on the rack. DC is inefficient for long distance, unless you are talking HVDC which is another story and it is disingenuous to act like they are comparable.
ISL 3y ago
AC came to predominate precisely because it is easier to work with at an infrastructure level. Stepping voltages with transformers is simple and easy. If you're AC all the way, there's never a need to rectify your generator, either.